1. Field of the Invention
The present invention relates to a stacked piezoelectric device used for a piezoelectric actuator and the like, and a method of fabricating the same.
2. Description of the Related Art
A piezoelectric device is characterized by generating force or displacement when voltage is applied, and by generating voltage when force is applied, and it has a wide range of application such as various actuators and sensors. A stacked piezoelectric device, which is a concept which includes a stacked piezoelectric actuator comprising a plurality of piezoelectric layers, is often used in order to obtain large generated force or displacement when it is used for an actuator and the like.
A common stacked piezoelectric device employs an expensive metal such as Ag/Pd as an internal electrode material from the restrictions on the manufacturing process, and therefore the manufacturing cost tends to become high remarkably as the number of stacked layers increases.
In order to attempt a cost reduction, for example, Japanese Unexamined Patent Publication No. 2000-340851 discloses that an internal electrode is formed by nonelectrolytic plating of Cu. Japanese Unexamined Patent Publication No. 2001-244519 discloses that piezoelectric material and Cu foil are bonded directly in the range of 500 to 700 degrees centigrade. However, a stacked piezoelectric device manufactured according to this prior art has an inadequate bonding strength for an operation with high load, and it lacks reliability. Moreover, Japanese Unexamined Patent Publication No. 2001-244519 discloses that bonding at a temperature of not less than 800 degrees centigrade is not preferable because it deteriorates the quality of piezoelectric material.